A small number of members have mentioned such a noise but I don't recall any definitive conclusion as to what's causing it. The exhaust was once thought to be the cause, but I'm not sure that would apply in your case (2016 or 2015 Mirage, UK market?)

More details might help us try to make sense of what's going on for you. A video could be especially useful.

I was told by a driver that one of the 17's has a noise at a certain rpm that sounded like a loose heat shield. I think it's the muffler. The car only has 40k. I banged on the exhaust with a rubber mallet near the rear cat and you can hear a faint rattle in the muffler. I pulled the exhaust out to take a closer look and compared it to a 15'. Both exhaust's are the same from the tailpipe to the front of the rear cat. The downpipe is longer on the 17'.Attachment 10008Attachment 10006 The seam on the muffler is right at the top and it's spot welded together. Maybe a week spot? It's like that on both the 15' and 17'. Attachment 10007 I'm able to reproduce the noise banging on the exhaust with it on the floor. It's the muffler for sure. It's weird that I can't get the same noise from the 15' exhaust. Both mufflers have the same part number-AB7001. Maybe it just rusted out faster or the extra length of downpipe just makes it rattle just right?